Kepler eBook

fulfilled. Another copy of the book Kepler sent
to Reymers the Imperial astronomer with a most fulsome
letter, which Tycho, who asserted that Reymers had
simply plagiarised his work, very strongly resented,
thus drawing from Kepler a long letter of apology.
About the same time Kepler had married a lady already
twice widowed, and become involved in difficulties
with her relatives on financial grounds, and with the
Styrian authorities in connection with the religious
disputes then coming to a head. On account of
these latter he thought it expedient, the year after
his marriage, to withdraw to Hungary, from whence he
sent short treatises to Tuebingen, “On the magnet”
(following the ideas of Gilbert of Colchester), “On
the cause of the obliquity of the ecliptic”
and “On the Divine wisdom as shown in the Creation”.
His next important step makes it desirable to devote
a chapter to a short notice of Tycho Brahe.

[Footnote 2: Since the sum of the plane angles
at a corner of a regular solid must be less than four
right angles, it is easily seen that few regular solids
are possible. Hexagonal faces are clearly impossible,
or any polygonal faces with more than five sides.
The possible forms are the dodecahedron with twelve
pentagonal faces, three meeting at each corner; the
cube, six square faces, three meeting at each corner;
and three figures with triangular faces, the tetrahedron
of four faces, three meeting at each corner; the octahedron
of eight faces, four meeting at each corner; and the
icosahedron of twenty faces, five meeting at each
corner.]

CHAPTER III.

Tychobrahe.

The age following that of Copernicus produced three
outstanding figures associated with the science of
astronomy, then reaching the close of what Professor
Forbes so aptly styles the geometrical period.
These three Sir David Brewster has termed “Martyrs
of Science”; Galileo, the great Italian philosopher,
has his own place among the “Pioneers of Science”;
and invaluable though Tycho Brahe’s work was,
the latter can hardly be claimed as a pioneer in the
same sense as the other two. Nevertheless, Kepler,
the third member of the trio, could not have made
his most valuable discoveries without Tycho’s
observations.

Of noble family, born a twin on 14th December, 1546,
at Knudstrup in Scania (the southernmost part of Sweden,
then forming part of the kingdom of Denmark), Tycho
was kidnapped a year later by a childless uncle.
This uncle brought him up as his own son, provided
him at the age of seven with a tutor, and sent him
in 1559 to the University of Copenhagen, to study
for a political career by taking courses in rhetoric
and philosophy. On 21st August, 1560, however,
a solar eclipse took place, total in Portugal, and
therefore of small proportions in Denmark, and Tycho’s
keen interest was awakened, not so much by the phenomenon,
as by the fact that it had occurred according to prediction.